Secondary tearing mode in the nonlinear evolution of magnetorotational instability

Numerical investigation of the two-dimensional magnetic reconnection is given in the context of the nonlinear evolution of the Magneto-Rotational Instability (MRI). With a careful comparison to various theories using both one- and two-dimensional analysis, it is found that a new stabilizing effect of the centrifugal force on tearing instability must be present in the specific geometry of the MRI. Magnetic reconnection might play a key role to the formation of the nonaxisymmetric structures observed in MRI experiments. The results may also be useful for the estimate of the accretion rate in various astrophysical objects. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.